Hazardous waste site cleanup is a major environmental concern, with contaminants at many sites posing an immediate environmental concern. Typically, these hazardous waste sites were created by the dumping of hazardous chemicals in inadequately designed dump pits or sites, such as bulk disposal or disposal in leaking or non-corrosion resistant containers. The chemicals at these sites accordingly seep into the underlying soils and into underlying aquifers. The movement of the contaminants within the soil and aquifers has resulted in large the contaminated areas, well beyond the actual dump site.
One method of decontaminating the hazardous waste sites was to completely remove the contaminated soil by excavation, followed by treatment of the removed soil at a processing facility or transport of the soil to another landfill site from which the spread of contaminants was more easily controlled. However, this method is very expensive and time consuming. Moreover, transporting the contaminated soil from one site to another only postpones the eventual treatment.
Another method for mitigating ground water contamination has been fluid removal. In fluid removal systems both drains and wells have been used. Typically, the use of drains involved excavating a pit located toward the downstream end of the contaminant plume. Prior conduit systems have been used for injection or removal of fluids. For example, Wang (U.S. Pat. No. 4,582,611) describes a corrugated drain having a porous filter. Variations use openings in the piping to provide openings for fluid transfer through the piping, as seen in Goughnour (U.S. Pat. No. 6,846,130) and Fales (U.S. Pat. No. 4,163,619). Beal (U.S. application Ser. No. 09/974,726) discloses a device comprising a tube containing baffles, which injects an oxidant to remediate a water borne contaminant as it flows through the device. Similarly, Swearingen, et al. (U.S. Pat. No. 8,210,773) uses piping systems to inject oxidant with the goal of removing pollutants from soil.
However, these drain systems have limited application to shallow plumes and in low permeability soils. Since drains are generally exposed to the surface, this remediation method is not desirable in flood-prone areas. Moreover, removal of contaminants with drain systems is often slow, commonly requiring many years to reduce the contaminants to an environmentally acceptable concentration.
Other systems for remediating contamination include conversion of landfills into bioreactors. For example, Hudgins, et al. (U.S. Pat. No. 6,364,572) provides aeration pipes that inject oxygen or ambient air into the landfill and leachate collection pipes that remove liquid forming in the landfill to provide an improved growth environment for microbes in the landfill, allowing for bio-degradation of contaminants. Similarly, Ankeny, et al. (U.S. Pat. No. 6,749,368) provides aeration pipes installed above a landfill, for injection of air into the soil and monitoring and extraction of contaminants.
Currently the industry (horizontal drilling) drill long continuous wells (several hundred to thousands of feet long) to do environmental work. The main drawback is the singularity of traditional wells.
However, these systems provide a simple conduit for direct pumping of fluid into the soil or removal of fluid from the soil. What is needed is a means to direct remediation materials to specific zones on subsurface structures to effectuate directed decontamination of a soil or other matrix.